Health officials are trying to track down the source of a stomach illness that’s causing flu-like symptoms in a rising number of people.

The infection, cyclospora, has been associated with imported fresh produce in past cases. It’s caused by a tiny parasite that is ingested through food or water.

Ten people have been hospitalized from the current outbreak, according to the Centers for Disease Control and Prevention. So far, the bug has hit over 250 people in Iowa, Nebraska, Texas, Wisconsin, Georgia and Connecticut since mid-June. Both the CDC and FDA are investigating.

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Most people start experiencing symptoms about a week after infection, although there are a range of symptoms, including diarrhea, loss of appetite, weight loss, stomach cramps, bloating, increased gas, nausea and fatigue. And some people who are infected don’t experience any symptoms, according to the FDA.

The illness can last anywhere from a few days to over a month, with symptoms coming and going.

Cyclospora is unlikely to be passed from person to person. The illness is endemic in some tropical and subtropical countries.

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While health officials continue tracking down the source, the FDA recommends preventing illness by washing all fresh produce and cleansing hands, utensils, and surfaces with hot, soapy water before and after handling food.

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